Percolation pond systems impacted by maintenance and construction work

This summer, water levels will remain low for a few percolation ponds in eastern parts of the county and south San José, due to a construction project near the Penitencia Water Treatment Plant and maintenance work on a major pipeline in South County.

A seismic retrofit project near northeastern San José will replace three large pipelines to address the seismic vulnerability of the Penitencia Delivery Main, Penitencia Force Main and the South Bay Aqueduct pipe systems. While the project has been in construction, the only source of water for neighboring ponds has been unavailable and water district groundwater replenishment operations have been limited. The affected pond systems in this region include the Piedmont Ponds near Toyon Elementary, Bob Gross Ponds, Helmsley Ponds, Capitol Ponds and the City Park Ponds in Penitencia Creek Park neighboring the Berryessa Community Center. Currently, the water district does not have water rights (or permission from the state) to divert natural creek water into these ponds.

The Penitencia Delivery Main and Penitencia Force Main Seismic Retrofit Project is estimated to be completed in the fall. However, the pipeline systems will be connected in the summer, so you may see water in the ponds as early as mid to late July. Pond levels may fluctuate this summer, due to a testing period of the pipeline system prior to completion of the seismic retrofit project.

In south San José, the water district will repair a valve located on a major pipeline that brings water into the valley through the pipeline. The valve requiring maintenance is located on our Cross Valley Pipeline, just north of Morgan Hill. This pipeline runs 8 miles through the cities of Morgan Hill and San José and delivers local and imported raw (untreated) water from the San Luis and Anderson reservoirs to the water district’s water treatment plants, and district-managed percolation ponds and creeks for groundwater replenishment.

In order to reduce the risk of causing more damage to the valve and pipeline, the water district has reduced the flow of water into the valley which has resulted in a lack of water being available for our percolation ponds and streams. Over the next few weeks water levels will decline in groundwater percolation ponds located in the Almaden Valley and Cambrian neighborhoods.The ponds most likely impacted by this temporary effort include Los Capitancillos, Alamitos, Guadalupe, and Kooser ponds.

Once we complete the required repairs, we anticipate being able to return to normal operations and resuming our recharge activities. Percolation ponds and releases to creeks are critical to our groundwater replenishment efforts and essential for our water supply. We are diligently working to get all systems back in service as soon as possible.

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